Abstracts of Papers Presented at the Third International Complement Workshop, Harvard Medical School, Boston, Massachusetts, June 3–5, 1968Specifically Purified Guinea Pig C′2
Partially purified guinea pig C′2 (Borsos, T., Rapp, H. J. and Cook, C. T., J. Immun., 87: 330, 1961) is adsorbed on EAC′4 (sheep erythrocytes carrying rabbit anti-Forssman and guinea pig C′4) suspended in 0.005 M Veronal buffer, pH 8.5, containing 0.059 M NaCl, 0.002 M MgCl2, and 5.8% sucrose. After two washings with the same buffer, the C′2 is eluted at 0°C with 0.005 M Veronal buffer, pH 6.5, containing 0.147 M NaCl and 0.05% gelatin. The product is stable and contains no guinea pig antigens other than C′2. However, it is contaminated with proteins from the sheep erythrocytes, mostly hemoglobin. For most purposes, this is not objectionable. If necessary, the contaminants may be removed by two successive electrophoretic separations on polyacrylamide gel. For improved stability, the C′2 is eluted from the gel with 0.005 M Veronal buffer, pH 7.4, containing 0.147 M NaCl and 0.05% gelatin, or with 0.15 M NaF containing 2% l-lysine.